Certified Rhythm Analysis Technician (CRAT) Practice Exam

When a ventricular pacemaker incorrectly senses electrical signals from outside the heart, the phenomenon known as oversensing occurs. Oversensing happens when the pacemaker misinterprets non-cardiac electrical signals, such as those from muscle contractions or external electrical interference, as intrinsic heart activity. As a result, the pacemaker may withhold pacing when it should be delivering it, potentially leading to bradycardia or missed beats since the pacemaker assumes the heart is functioning normally.

Understanding this aspect of pacemaker function is crucial for ensuring proper heart rhythm management, particularly in patients with certain heart conditions. The other options reflect different pacemaker issues that do not relate to the misinterpretation of external signals.